In a conventional semiconductor device disclosed in a patent document 1 for example, it is proposed to provide a layer of electrically insulating epoxy resin powdery paint having a function of a highly thermally insulative insulating sheet or a resinous thermal resistor on a surface portion of a thermally conductive electrically insulating spacer on which the element is disposed excluding the area where a semiconductor element is attached under pressure.
On the other hand, in an electrical device such as a semiconductor device having a heat generating electrical element and a housing including a heat dissipating substrate for supporting the heat generating electrical element and dissipating heat from the heat generating electrical element and a housing cover surrounding the heat generating element, the housing is required to have a heat resistance. When the heat generated is relatively of small amount and a relatively low temperature can be maintained due to the heat dissipation through the heat dissipation substrate, a heat resistant resin such as PPS can be used for the housing, thereby maintaining the housing cost low.
Also, in the conventional electrical device, as disclosed in Patent document 2, for example, nothing is inserted between the semiconductor device and a copper plate (bus bar) for electrical connecting an electric motor and a capacitor.
In the inverter constructed using the power module disclosed in this document, one module includes output terminals for U-phase (or V-phase, W-phase), P-phase, N-phase and a control terminals, and three modules constitute the inverted. U-, V- and W-phases are connected to an electric motor, P-, N-phase are connected to a smoothing capacitor, an electric source or a converter. The control terminal is connected to a gate driver for controlling the operation of the module.    Patent document 1: Japanese Patent Laid-Open NO. 9-219970    Patent document 2: Japanese Patent Laid-Open NO. 11-265969